The present invention relates to a transfer device in manufacturing systems for tobacco products.
In the art field of manufacturing and packing systems as used in the tobacco industry, it is common practice for tobacco products, and in particular cigarettes, to which reference is made by way of example in the following specification, to be transferred en masse utilizing belt or chain type conveyors.
The purpose of such an operation is to take up cigarettes from a first machine of the system, a cigarette maker for example, and feed them continuously in a loosely arranged but ordered flow to a second machine of the system such as a packer, by which the cigarettes are wrapped in groups.
The cigarettes making up the ordered flow are disposed transversely to the conveying direction, lying one on top of another, en masse, in such a way as to form a layer of substantially constant depth.
It is common practice likewise for the transferred cigarettes to be conveyed along paths typically including straight, inclined and curved stretches.
It will often be the case that a buffer storage unit is located between the maker and the packer, to compensate for differences in their rates of output. In this instance, the cigarettes are conveyed along a spiral path for a certain distance.
Conventional conveying systems comprise a plurality of modular elements fashioned from rigid plastic material, connected one to the next by hinge means in such a way as to form a continuous and flexible chain loop passing around guide and support rollers.
The single modular elements, produced by a molding operation, are fashioned with a flat top serving as a transport surface, and a body molded integrally with the flat top, which is connected to the modular elements on either side by way of the aforementioned hinge means.
The flat tops of the elements combine to create a substantially continuous surface on which the layer of cigarettes is supported and transferred.
In prior art embodiments, to ensure the cigarettes grip the conveyor firmly and consequently prevent any possibility that the advancing layer of cigarettes could slip during the course of the transfer, especially on the curved and inclined stretches, a relatively soft facing material is applied to the transport surface of each modular element, by means of an adhesive, such as will increase the friction coefficient of the conveying surface.
In practice, it has been found that with the system in operation, fragments of the aforementioned high friction facing material can be caused by a combination of mechanical stresses and wear to break off, whereupon these same fragments are able to reach the packer quite easily and find their way together with the groups of cigarettes into the single packets.
If packets containing this foreign matter are not immediately detected and discarded, they will be distributed and retailed, with the result that the manufacturer must obviously suffer damage through loss of image.
The object of the present invention is to provide a conveyor device for tobacco products that will be unaffected by the drawbacks described above with reference to the prior art.